This invention relates to intraocular lenses and, more particularly to a lens which employs a fluid as its primary lens medium.
Intraocular lenses generally consist of a medial lens body and a plurality of lateral lobes or position fixing elements (haptics) projecting from the circumference of the lens body for fixing the lens in the eye. The insertion of such a lens in the eye requires the surgeon to make a corneo-scleral incision sufficiently long to not only accommodate the passage of the lens, but also the position fixing haptics. Historically, the length of such an incision has approximated 6 to 9 mm.
Efforts have been made, and continue to be made to reduce the length of the required incision by redesign of the lens structure. In my copending patent application, entitled "Intraocular Lens with Retractable Legs", Ser. No. 649,798, I describe an intraocular lens wherein the positioning haptics are held in a retracted position until the lens is inserted in the eye, at which time the surgeon releases the haptics which automatically act to properly position the lens. Such a lens structure enables the surgeon to emplace with ease, the lens in the capsular bag and assures the least traumatic effect on the patient.
Other intraocular lenses of different design, but whose purpose is to reduce the dimension of the surgeon's incision, are shown in U.S. Pat. Nos. 4,296,501 and 4,343,050 to Charles Kelman.
All of the above-mentioned lenses are "solid" in that their minimum size is determined by the size of the lens element, notwithstanding what is done to the lens' positioning elements. In U.S. Pat. No. 4,466,705 of Paul Michelson, an intraocular capsular lens is described whose lens medium is a liquid material. Michelson's capsule is constructed of a semipermeable transparent membrane which is inserted in a dehydrated state into the eye. The capsule then hydrates and expands to a lens-like shape. Since the lens is inserted in a dehydrated state, Michelson suggests that it can be inserted through a small incision by folding or rolling it into a compact form. While this design does substantially reduce the size of the required incision (to 3 or 4 mm), the final lens configuration is difficult to control. In addition, there is no way to correct for any malformation of the lens once it is in place, if for any reason, the lens does not hydrate in accordance with expectations.
Recently, it has been reported that cataracts may be removed by phacoemulsification through a one millimeter non-sutured incision (ie. see Shearing, et al. pp. 6-11, CATARACT January 1985). Unfortunately there has been no intraocular lens which could be inserted through such a small incision.